I agree 100% with Terry here.
I didn't even know that Nakamichi made car speakers. Odds are that it is a relabeled speaker of somebody else's provenance. I would avoid until hearing them for yourself.
I would also really advise you NOT to buy speakers unheard over ebay and instead go to a store and actually hear the speakers for yourself. You would be surprised at how different a lot of them sound.
If you are in that price range, Terry is right on with the Infinity and JBL picks (those 6x9 JBL are really nice, btw); you may also want to check out Rockford Fosgate speakers and some of the lower-end Boston Acoustics.
Also, if you go with an Alpine head unit, it should have enough onboard power to drive any of the speakers mentioned here. No amp required, but you may want to check with those Infinity separates.
I have all Phoenix Gold accessories and wires in my car system. Some of my interconnects are Monster, but all the heavy-duty stuff (distributor block, fuse box, 2-gage wire, etc.) is Phoenix Gold. Monster is probably the most popular, however.